Composite fabrics for use in surgical gowns, surgical drapes and the like, are well known. The purpose of these fabrics is to place a bacteria barrier between the aseptic operative field and areas which are incapable of surgical cleansing. It it essential that such fabrics possess a high liquid strikethrough resistance (measured by the hydrostatic head test), high bacteria strikethrough resistance, and adequate strength and tear resistance. These fabrics should be sufficiently flexible and drapable. The operating room gown, in particular, must function, during the course of an operation, to prevent contamination of the patient, surgical instruments and other personnel through contact with the wearer and to prevent clothes of the wearer from becoming saturated with blood and other liquids. Previous operating room gowns composed of a melt blown layer or layers with one or two reinforcement layers of nonwoven fabric, generally have the deficiency that as the laminated composite is extended, as in the case of the surgeon bending his elbow, the melt blown fabric develops holes and loses its barrier properties. (These barrier properties can be measured by the hydrostatic head test described hereinafter.) The melt blown fabric has a lower elongation than that of the reinforcing layer or layers, so that during extension of the composite, the melt blown fabric will fail (rupture) before the reinforcing layers fail. Thus, it is of little use to provide a high tensile strength reinforcing layer if the barrier properties of the composite are lost by extension of the melt blown fabric.
In accordance with the present invention, a creped microfine fiber layer (preferably melt blown) is incorporated as the barrier layer. As a result thereof, the extension of the laminated fabric will not cause deterioration of the barrier properties until much higher levels of extension are reached. In addition, a much softer fabric laminate will also result due to the much greater extensibility of the microfine fiber layer. Furthermore, the microfine fiber (melt blown layer) may be creped to a sufficient degree of compaction such that it will be virtually unaffected at the rupture elongation of the reinforcing layer or layers.
Although the microfine fibers utilized in the present invention are preferably produced by melt blowing, such microfine fibers can also be produced, for instance by a centrifugal spinning operation (see Vinicki's U.S. Pat. No. 3,388,194) and by other methods.
Although the laminate of the present invention is particularly useful in the case of operating room gowns which are subject to considerable extension at the elbows, nevertheless such laminate is also suitable for use as an operating room drape, a tray cover for surgical instruments, laparotomy packs, obstetric packs, backing layers for diapers or sanitary napkins and for any other application wherein an impermeable material would be desirable. The material is also suitable for surgical face masks.